add path for post sign-in from mobile
changed int type of is_mobile flag in SessionsController to string stype
return user name as welcome message
changed error status when cannot authorized user to 401
add microposts and getting microposts
changed output of get_posts for easier parsing :P This is only temporary
allowed post method for testing of android application where get is not yet implemented
fixed bug in checking for user logging in
moved getting user posts to show and incorporate mobile flag
fix login so that it returns user id